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Enhanced Pulse Compression Induced by Third-Order Dispersion in Birefringent Fibre

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Chinese Physics Letters 2001年第9期18卷 1211-1213页

作者： XU Wen-Cheng CHEN Wei-Cheng LUO Ai-Ping GUO Qi LIU Song-Hao Institute of Quantum Electronics South China Normal University Guangzhou 510631

We report on the enhanced pulse compression due to the interaction of positive third-order dispersion and cross-phase-modulation effects in birefringent fibres. Polarization soliton compression along the slow axis can be enhanced in birefringent fibres with positive third-order dispersion, and the polarization soliton compression along the fast axis can be enhanced in fibres with negative third-order dispersion. Moreover, the third-order dispersion parameter can be optimized to obtain the optimal pulse compression.

关键词： polarization pulse soliton

ON THE RAYLEIGH QUOTIENT FOR SINGULAR VALUES

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Journal of Computational Mathematics 2007年第5期25卷 512-521页

作者： Xiaoshan Chen Wen Li School of Mathematical Sciences South China Normal University Guangzhou 510631 China

In this paper, the theoretical analysis for the Rayleigh quotient matrix is studied, some results of the Rayleigh quotient （matrix） of Hermitian matrices are extended to those for arbitrary matrix on one hand. On the other hand, some unitarily invariant norm bounds for singular values are presented for Rayleigh quotient matrices. Our results improve the existing bounds.

关键词： The singular value Rayleigh quotient Canonical angle matrix

Direction-Dependent Switching in Nonlinear Chirped Gratings

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Chinese Physics Letters 1996年第4期13卷 285-288页

作者： LIU Jun-min LIAO Chang-jun LIU Song-hao XU Wen-cheng Institute of Quantum Electronics South China Normal UniversityGuangzhou 510631

Chirped gratings with uniform Kerr nonlinearity are numerically demons traced to have direction-dependent switching behavior,which is caused by the different energy storage between the two incident *** effect can iind... 详细信息

关键词： Chirped optical Switching

Higher-Order Dispersion and Soliton Pulse Compression in the Dispersion-Decreasing Fibers

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Chinese Physics Letters 1997年第4期14卷 298-301页

作者： XU Wen-cheng GUO Qi LIU Song-hao Institute of Quantum Electronics South China Normal UniversityGuangzhou 510631

The compression results of picosecond and femtosecond soliton pulses in the dispersion-decreasing fibers are reported in this *** found that the high-order dispersion has a great influence on the soliton *** expressio... 详细信息

关键词： fiber soliton Dispersion

ASYMPTOTICS FOR POSITIVE SOLUTIONS OF THE WEIGHTED LAPLACE EQUATIONS INVOLVINGCRITICAL GROWTH

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Acta Mathematica Scientia 2000年第1期20卷 12-18页

作者：耿堤 Department of Mathematics Huanan Normal University Guangzhou 510631 China

A general weighted second order elliptic equation involving critical growth is considered on bounded smooth. domain in n-dimension space. There is the singular point for the weighted coefficients in the domain. With generalized blow up method, some results are obtained for asymptotic behavior of positive solutions. This problem includes Laplacian operators as special cases.

关键词： weighed Laplace operator asymptotic behavior critical exponents the Green's function

Regio-and Diasteroselectivity of Rhodium-catalyzed Ring Opening Reaction of Oxabenzonorbornadienes with Heteroatom Nucleophiles

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Chinese Chemical Letters 2003年第7期14卷 697-699页

作者： Ding Qiao YANG He Ping ZENG Department of Chemistry South China Normal UniversityGuangzhou 510631

A new rhodium catalyzed ring opening reaction of oxabenzonorbornadienes and its derivatives was described. This reaction forms a new carbon-nitrogen bond via an intermolecular allylic displacement of the bridgehead o... 详细信息

关键词： Ring opening rhodium-catalyzed oxabenzonorbornadienes heteroatom nucleophiles.

Enhanced Transmission Stability of Polarization Solitons in Birefringent Fibres With an Optical Phase Conjugator

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Chinese Physics Letters 2003年第8期20卷 1286-1289页

作者：陈伟成谢嘉宁路洪徐文成 DepartmentofPhysics FoshanUniversityFoshan528000 InstituteofQuantumElectronics SouthChinaNormalUniversityGuangzhou510631

An optical phase conjugator is used to enhance transmission stability of polarization solitons in highly birefringent fibres. Two polarization solitons form a breather in fibres with low birefringence firstly and the optical phase conjugator is used to make the spectra of polarization solitons converse, which results in the fact that the polarization soliton along the fast axis is compressed due to the strengthened self-phase modulation effect. Two polarization solitons are compressed further due to the cross-phase modulation effect. The enhanced nonlinear effects make the central peak frequencies of two polarization solitons shift to the larger range in opposite directions so that they trap each other fully to suppress the effect of birefringence.

关键词： Solitons

Synchronous detection of glutathione/hydrogen peroxide for monitoring redox status in vivo with a ratiometric upconverting nanoprobe

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Nano Research 2019年第4期12卷 931-938页

作者： Judun Zheng Yunxia Wu Da Xing Tao Zhang MOE Key Laboratory of Laser Life Science & Institute of Laser Life Science South China Normal University Guangzhou 510631 China College of Biophotonics South China Normal University Guangzhou 510631 China

Cellular redox status presents broad implications with diverse physiological and pathological processes. Simultaneous detection of both the oxidative and reductive species of redox couples, especially the most representative pair glutathione/hydrogen peroxide (GSH/H2O2), is crucial to accurately map the cellular redox status. However, it still remains challenging to synchronously detect GSH/H2O2 in vivo due to lack of a reliable measuring tool. Herein, a ratiometric nanoprobe (UCNP-TB) possessing simultaneous delectability of GSH/H2O2 is established based on a multi-spectral upconverti ng nano phosphor (UCNP-OA) as the lumin esce nee res onance energy tran sfer (LRET) donor and two dye molecules as the acceptors, including a GSH-sensitive dye (TCG) and a H2O2-sensitive dye (BCH). With the as-prepared UCNP-TB, real-time and synchronous monitoring the variation of GSH and H2O2 in vitro and in living mice can be achieved using the ratio of the upcon versi on lumin esce nee (UCL) at 540 and 650 nm to that at 800 nm as the detecti on sign al, respectively, providi ng highly inhere nt reliability of the sensing results by self-calibrati on. Moreover, the nan oprobe is capable of mappi ng the redox status within the drug-resista nt tumor and the drug-induced hepatotoxic liver via ratiometric UCL imaging. Thus, this nan oprobe would provide a reliable tool to elucidate the redox state in vivo.

关键词： redox status glutathione hydrogen peroxide upconversion imaging nanoprobe

Studies on threshold pressures of sonoluminescence for bubbles with different noble gases

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Science China(Physics,Mechanics & Astronomy) 2004年第4期47卷 513-520页

作者： DING Chunfeng XING Da Institute of Laser Life Science South China Normal University Guangzhou 510631 China Institute of Laser Life Science South China Normal University Guangzhou 510631 China

The noble gases inside bubbles may have a profound effect on the threshold pressure of sonoluminescence (SL). In this work, the SL threshold pressures have been measured experimentally for bubbles with different noble gases. Results show that the threshold pressure increases with the decrease of molecular mass for gases inside the bubbles. The simulating temperature values at the collapse are almost equal to each other for different gas bubbles at the threshold pressures. However, when the pressure is above the threshold one, the SL mechanism satisfies the bremsstrahlung. On the basis of the experiments and simulations, we found that firstly water molecules dissociate in the process of cavitation and light emission follows; then, the noble gases ionize with the increase of temperature and the bremsstrahlung occurs. SL is a process from molecular emission to bremsstrahlung.

关键词： noble gases, threshold, molecular emission, bremsstrahlung.